Macrophage-derived exosomes carrying RAD50 attenuate oxidative DNA damage and p53–p21-dependent S-phase arrest in spermatogenic cells

<p>Occupational heat and blast overpressure impair spermatogenesis, and whether repair capacity supplied from outside the germ cell can lift the resulting block has not been tested.</p> <p>GC-2 spermatocytes received 1000 shock-wave pulses then 100°C for 40 s, and C57BL/6 mice received a 10% methane blast with intratesticular temperature unrecorded. Both were treated with exosomes from J774A.1 macrophages profiled by nanoparticle tracking and proteomics.</p> <p>Stress raised mitochondrial superoxide, lowered membrane potential and generated phosphorylated H2A.X (γ-H2AX) foci.

Across 675 differentially expressed genes, glutathione metabolism was the most enriched pathway, at 7.13-fold and adjusted <i>p</i> = 7.07 × 10⁻⁶. p53 and p21 increased while cyclin-dependent kinase 2 (CDK2) and Cyclin A2 decreased, arresting a larger fraction of cells in S phase than in controls. RAD50 was detected among 3603 exosomal proteins and ranked in the top tier of the displayed abundance panel, and exosome treatment increased its co-precipitation with MRE11.